So...i asked you to tell me more more about how they WITNESSED it. Because the OP claimed that we weren`t here to witness the saying of the bible which means its false according to him. not some explanation they try to come up with. and even in that big bang theory link it says:

''Although generally accepted as the model for the origin and evolution of the universe, the Big Bang theory is not complete. For example, it does not explain what caused the initial expansion or why galaxies formed.''